On 8/7/10 3:14 AM, dagss wrote:
On Aug 3, 5:52 am, Jason Grout<jason-s...@creativetrax.com> wrote:
6. TRANSPOSE/CONJUGATE
It seems that implementing this would just involve modifying the
__pos__(self) method for complexes, matrices and complex matrices, and
I think that both conjugating and transposing are common enough
operations to deserve its own operator.
Numpy has:
m.T for transpose
m.H for hermitian
m.I for inverse
(seehttp://www.scipy.org/NumPy_for_Matlab_Users312)
I think it would be great if we had similar shortcuts.
I always assumed that the lack of these was just that nobody had
bothered to implement them, not that anyone were actually against
them?
Well, there is a general trend towards using functions instead of
attributes in Sage. I think the main reason is for documentation (I
wish python had attribute docstrings that we could query!).
However, in this case, I think it makes a lot of sense to have m.T
instead of m.T() (my reasoning is that you are usually using these in
formulas, and the extra set of parentheses makes your formula look a lot
more complicated and harder to parse).
a) At least the .T is so completely ingrained into the NumPy/SciPy
community that it would at least be very strange to go with some
*other* form of operator (like has been proposed)
b) It's Python compatible
c) It's incredibly convenient.
+1 to .T and .H.
BUT, -1 to .I for the inverse, because the *intent* of
arr.I * x
is almost certainly arr.solve_right(x). Actually taking the inverse,
"arr.inverse()", is something you rarely want to do, and in those
cases, having to type out "inverse" is a good thing IMO. Just keeping
shorthand syntax like that out helps reduce bad habits.
I usually just use python's inverse operator:
~A
Jason
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